In a statement by Garba Shehu, presidential spokesperson, Buhari described the execution as evil.
He added that his administration will not lower its guards in the war against terrorism.
“I am profoundly saddened and shocked by the death of innocent hostages in the hands of remorseless, godless, callous gangs of mass murderers that have given Islam a bad name through their atrocities,” the president said.
“We should, under no circumstance, let the terrorists divide us by turning Christians against Muslims because these barbaric killers don’t represent Islam and millions of other law-abiding Muslims around the world.
“As a President, the collective security of all Nigerians is my major preoccupation and the death of an innocent Christian or Muslim distresses me.
“No true Muslim would be shouting ‘Allahu Akbar’ while killing innocent people, an evil frequently condemned by the Holy Qur’an.
“These agents of darkness are enemies of our common humanity and they don’t spare any victim, whether they are Muslims or Christians, and therefore, we shouldn’t let them divide us and turn us against one another.
“The goal of these psychopaths is to cause confusion and spread distrust between Muslims and Christians, despite the fact that they aren’t representing the interest of Muslims or Islam.”
Buhari also said he will continue to intensify efforts towards strengthening international cooperation and collaboration to break the backbone of the terrorists.